class_docstr: Stores/loads data to increase performance.
  
  :param cache_db: specific DB for specific data
docstr: Returns percent of how many elements were loaded instead of computing.
docstr_tok: ["Returns","percent","of","how","many","elements","were","loaded","instead","of","computing","."]
code: def effectiveness_ratio(self):
      """
      Returns percent of how many elements were loaded instead of computing.
      """
      if self._db.use_stats:
          #  Result order corresponds to the order in self.db._effectiveness_keys
          eff_dct = {}
          returned_eff = self._db.get_effectiveness()
          for key, hit, total in zip(
              self._db.get_effectiveness_keys()[::2],
              returned_eff[::2],
              returned_eff[1::2],
          ):
              key = key.split("_")[0]
              eff_dct[key] = round(hit / total, 3) if total else 0.0
          return eff_dct
  
file_path: FEDOT/fedot/core/caching/base_cache.py
imports: from typing import Union
  from golem.core.log import default_log
  from golem.utilities.singleton_meta import SingletonMeta
  from fedot.core.caching.pipelines_cache_db import OperationsCacheDB
  from fedot.core.caching.preprocessing_cache_db import PreprocessingCacheDB
label_desc: Use image node_id 2 for calling the BaseCache obj's underlying member method code with example usage: obj.effectiveness_ratio() and returns: eff_dct